Mild 360 Magnum Build

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ir3333 said:
”you know what you should have done".
Click to expand...
Oh yea! Everyone’s favorite arm chair 1/4 back statement like they know what YOU had in mind.
As well as the underlying statements of ether/or “You don’t know what your doing” / “I know how to make it better and not leave power on the table like you did.”
 
rumblefish360 said:
Oh yea! Everyone’s favorite arm chair 1/4 back statement like they know what YOU had in mind.
As well as the underlying statements of ether/or “You don’t know what your doing” / “I know how to make it better and not leave power on the table like you did.”
Click to expand...
I ,won't go there .. I admit my mistake (s).., and try to help perspective by my mistake (s)..
RESEARCH EVERYTHING !!!!!
 
Well all I gots to say...
I did it my way.png
 
Back to the original post.
If using a magnum block, rod and crank and putting a la piston on it, wouldn't that give you a positive deck height.
I thought that the deck height on the Magnum was less than the deck height on the LA.
 
My next question on your build is what are you doing for oiling system modifications?
The reason I'm asking these questions is I purchased a rusty 5.9 Magnum block and I have a set of flat top 360 Pistons with rods and crank from a LA motor that are 30 over.
So far the only thing I have done to The oiling system is to drill number 2 3 and 4 Passage for the mains out to 9/32.
 
Pistons,bearings and other bottom end parts showed up

65EA6419-683C-4ABA-B27A-D3BCEAC056C1.jpeg
 
Jadaharabi said:
Back to the original post.
If using a magnum block, rod and crank and putting a la piston on it, wouldn't that give you a positive deck height.
Click to expand...
Not necessarily. That depends on the height of the piston.
I thought that the deck height on the Magnum was less than the deck height on the LA.
Click to expand...
It is but not by much. The exact amount will vary as the LA engines did not always come with a uniform Deck height. The magnum was much better at this.
 
Jadaharabi said:
My next question on your build is what are you doing for oiling system modifications?
The reason I'm asking these questions is I purchased a rusty 5.9 Magnum block and I have a set of flat top 360 Pistons with rods and crank from a LA motor that are 30 over.
So far the only thing I have done to The oiling system is to drill number 2 3 and 4 Passage for the mains out to 9/32.
Click to expand...
I’m not doing anything to the oiling system other than putting the right pan on it to fit the car... I will measure everything and calculate the compression ratio before I pull the trigger on the cam in case it’s too low for the one that was recommended to me
 
Jadaharabi said:
Back to the original post.
If using a magnum block, rod and crank and putting a la piston on it, wouldn't that give you a positive deck height.
I thought that the deck height on the Magnum was less than the deck height on the LA.
Click to expand...
The Magnum is nominally .015" lower. I am trying to think of any stock-ish LA pistons to fit in a 360 bore that would be positive deck with a Magnum deck but am drawing a blank... except for an early 340 which is positive over an LA deck height too. H116CP's would be .012 below a Magnum deck.

The pistons that the OP shows will be around .067" below the Magnum deck; not likely to have much quench effect. FWIW.. they are middlin' compression; dish volume is 11.2 cc for the FM cross-catalog part. SCR around 8.8 with standard Magnum heads and a tad higher with a .028" thick head gasket.... certainly better than the LA and LA heads.
 
even worse
Silvolite Piston - 5.9L Chrysler (V8) 1971-81 1273 Chrysler 1971-81 360 5.9 4 1.576 CH 0.9842 flat top 9:1
Silvolite Hyper-Coated Piston - 5.9L Chrysler (V8) 1971-941279HC 1971-94 360 5.9L 4.000 1.576 CH .912 7.5cc 8-8.4 cr 3.130 x.050 deep recess 7.5cc
piston in hand
3222HC 1.605 CH 10cc dish .080 deep Hyper
1.675 CH
KB 232 18cc
KB373 2.8cc
KB 362 19.4cc
KB 190 -1.2cc
KB 191 -11.2cc
KB 107 5cc

so how do you make that 1.605 compression height piston work? looks like a 1.675 ch piston with a dish would give you quench and whaterver compression ratio you want?
 
Wyrmrider said:
KB 232 18cc
KB373 2.8cc
KB 362 19.4cc
KB 190 -1.2cc
KB 191 -11.2cc
KB 107 5cc
Click to expand...
For those who don’t know, the minus sign next to the piston number is valve relief and / or effect dome size is A notation sign meaning positive deck height.

Correct wyrmrider?
 
FWIW..... In the KB world, + is actually valve relief and increases chamber volume (lower CR), and - is for a pop-up or dome, i.e., it decreases the chamber volume (higher CR). Other piston mfr's use the opposite convention. How you know is to look at a flat top that the mfr makes with eyebrows and look at their listing for whether the sign the eyebrow volume as + or -. I always go to the pistons mfr sheet as a distributor site's listing might make a mistake.

Every mfr references it relative to a perfect flat top (no reliefs) with it's flat plane defined by the compression height +rod length + 1/2 of the stroke - deck height. You can have both eyebrows AND a dome which change the CR in opposite directions, but the number shown, + or -, is the net total change from that perfect flat top model.
 
Lots of interesting piston information you are sharing, the ones I ordered look to be stock knock offs in 30 over... just want to be able to fill the tank with 87 and I will try to make 375hp in the very low 5000rpm range
 
correct rumble ---------------cc 59 -61-- 62 64 68 72 figured with 9.599 crank to deck
KB 232 18cc .050 quench head && ---- 9.5 9.3 8.9 8.6 .280 valve depth in dish
KB373 2.8cc .085 quench head $$-------11.2 22.0 10.5 10.0 has trough valve reliefs .286
KB 362 19.4cc step dish-## 9.5 9.4-------9.1 ----------------.280
KB 190 -1.2cc solid dome **x---xxx11.8 11.5 10.9 10.5 has trough valve reliefs .336 both same
KB 191 -11.2cc solid dome ** x--***-13.6 13.2 12.5 11.8 has trough valve reliefs .331 ex .343 int ICON IC 743 60ccc 14:1 65=13 70=12 Eddie OK
KB 107 5cc --------flat top **x--***-10.9 10.7 10.2 9.8 has trough valve reliefs .280 ICON IC 741 62 11.2 65 10.5 70 10.0
IC 742 9.6cc ---dish 60cc 10.6 65cc 10.0 70cc 9.5 LA rod small end must be narrowed to 1.00". ex .231 int .243

.## Piston may protrude on 1992 and up Magnum truck blocks. LA rod must be narrowed to 1".
$$ Piston may protrude on 1992 and up Magnum truck blocks. Quench dome elevated .085".
Machining required to achieve optimum quench. Will not work with Magnum or Edelbrock closed chamber heads
&& Piston may protrude on 1992 and up magnum truck blocks. Elevated quench dome .050" tall.
** Piston may protrude on 1992 and up magnum truck blocks. .070 oversize can be used with 340 block and 360 crank. (if available)
 
not stock knock offs
re-builder pistons with reduced compression height (compensated pistons)
you want to make hp on regular gas you need some tight quench
open chamber heads take rpm (more cam, gears, converter) and high octane to make horsepower
I helped design the quench head pistons/ step dish pistons working with John Erb at KB- others smarter than I - some with propane experience- a real genius, and Speed-O Motive (they have left the strip I'm sad to say) also helped to solve the problem with the MOPAR open chamber heads. Speed-O-Motive used to weld up the chambers- it's that bad
what cc your heads- have you checked them yourself?
 
67autocross said:
Lots of interesting piston information you are sharing, the ones I ordered look to be stock knock offs in 30 over... just want to be able to fill the tank with 87 and I will try to make 375hp in the very low 5000rpm range
Click to expand...

Don't know if you've seen this but it may help. It's pretty much exactly what you are wanting to do--done the same way you are. J.Rob
360 TrueStreet Magnum Build
 
Wyrmrider said:
you want to make hp on regular gas you need some tight quench
open chamber heads take rpm (more cam, gears, converter) and high octane to make horsepower
I helped design the quench head pistons/ step dish pistons working with John Erb at KB- others smarter than I - some with propane experience- a real genius, and Speed-O Motive (they have left the strip I'm sad to say) also helped to solve the problem with the MOPAR open chamber heads. Speed-O-Motive used to weld up the chambers- it's that bad
Click to expand...
So I gotta ask.... do you remember the TRW pistons that would fill part of an open chamber head with a very tightly contoured dome to get some quench effect in an open chamber head? (I had a set in my 351C.)
 
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